In conventional surface emitting semiconductor lasers having an optically pumped vertical emitter and an integrated pump laser for optically pumping the vertical emitter, the generated radiation can be coupled out on the substrate side in order to improve the heat dissipation (“bottom emitter”). During the production of the epitaxial layer sequence, in this case the pump laser is arranged on a substrate and the vertical emitter is arranged on that side of the pump laser which is remote from the substrate. For the purpose of thermal coupling, on that side of the vertical emitter which is remote from the substrate, an galvanic layer containing gold, for example, is applied and subsequently planarized.
An optoelectronic component which has a semiconductor body with a vertical emitter region and a monolithically integrated pump source is known from DE 10 2006 024 220, U.S. equivalent Patent Application Publication No. 2009/0304039 A1, for example.
A method for producing semiconductor chips which have an galvanically applied reinforcement layer consisting of gold is known from the document DE 100 40 448 A1, U.S. equivalent U.S. Pat. No. 7,678,591, for example. In this case, an active layer is grown onto a substrate. Rear-side contact layers are formed on the active layer, a gold layer being applied to said contact layers by means of electroplating. After an auxiliary carrier layer has been applied to the reinforcement layer galvanically, the substrate is separated from the active layer.
The galvanically produced layer can lead to great strains, whereby further processing is adversely affected. Furthermore, strains can lead to damage within a semiconductor laser and, as a result, to a shorter service life.
Furthermore, great strains can make it more difficult to produce the surface emitting semiconductor laser. By way of example, strains which can arise as a result of the galvanic layer make it more difficult to process a plurality of semiconductor lasers on a common carrier body or wafer having a size of 100 mm or more, that is to say to produce semiconductor lasers in the wafer assemblage for mass production. By way of example, strains in the layers in the wafer assemblage can lead to warpages or cracks in the wafer which impede further processing of the wafer assemblage.
Furthermore, in conventional surface emitting semiconductor lasers which couple out the generated radiation on the substrate side, it is necessary to etch a light exit opening into the substrate for the purpose of coupling out radiation.